This invention relates generally to the field of vehicle wheel structures. More specifically, the invention relates to an improved hub for the axle of a spoked wheel for a bicycle, motorcycle, or the like, wherein the improvement provides for a more efficient application of torque between the hub and the spokes, and thus a more efficient transfer of rotation-inducing power from the axle to the rim through the hub and the spokes.
The typical prior art spoked wheel for a bicycle, for example, includes a cylindrical axle with a circular hub at both ends. As shown in FIG. 7, each hub 10 has an annular peripheral portion 12 with an outer surface 14 and an inner surface (not shown). A first plurality of spokes 16 is attached to the outer surface 14 of the peripheral portion 12 at a first plurality of equidistantly-spaced attachment apertures 18, each spoke 16 in the first plurality of spokes forming an equal angle .alpha. with respect to a radius R of the hub that passes through a point on the peripheral edge of the hub directly underlying the spoke 16. A second plurality of spokes 20 is attached to the inner surface of the peripheral portion 12 at a second plurality of equidistantly-spaced attachment apertures 22, each spoke 20 in the second plurality of spokes forming an equal angle -.alpha. with respect to the radius R of the hub. The angle -.alpha. is equal in magnitude to the angle .alpha. of the first plurality of spokes, but oppositely directed, so that the spokes of the first and second pluralities cross over each other and the radius R near the periphery of the hub at an angle having a magnitude of 2.alpha..
One drawback to the above-described arrangement is that the torque applied to the spokes by the rotation of the wheel tends to cause the spokes to pivot around their attachment points on the hub, so as to displace the spokes from their nominal angular orientations, as shown by the broken outlines in FIG. 7. One consequence of such pivoting and angular displacement of the spokes is a loss of rotation-inducing power transfer between the hub and the rim. Another consequence is the gradual weakening of the spokes due to the stresses and strains of the pivoting and displacement.
Accordingly, there has been a long-felt need for a simple, cost effective mechanism for substantially reducing the above-described pivoting and displacement of the spokes.